Wound package

ABSTRACT

Synthetic plastic tape drawn from a controlled speed supply source is wound on a nonrotary support by means of mechanism comprising a winding guide for the tape which is driven round the axis of the support, while a relative axial traversing motion takes place between the guide and the support, so as to apply one turn of twist for each revolution of the guide. The tape is fed to the winding guide in a generally axial direction from a letoff guide and at a tension such that the twist is applied in a controlled manner represented by localized folds to give a package from which the tape can be unwound overend in a twistfree condition.

United States Patent [72] inventor John Kay Pringle Mackie Belfast, Northern lreland [2| Appl. No. 795,765

[22] Filed Dec. 13, 1968 Division of Ser. No. 665,615, Sept. 5, 1967, Pat. No. 3 .449,901.

[45] Patented Feb. 2, 1971 73 Assignee James Mc'kie sis-Th3 Limited Albert Foundry, Belfast, Northern Ireland a British company [32] Priority Sept. 8, 1966 [33] Great Britain [31 40,223/66 [54] WOUND PACKAGE 6 Claims, 6 Drawing Figs.

[52] US. Cl... 242/159 [51] Int. Cl B65h 55/00 [50] Field of Search 242/l59, 163, 174-178; 57/157, 66, 67, 71, 74

[56] References Cited UNITED STATES PATENTS 3,383,851 5/1968 Hickman 242/159X Primary ExaminerStanley N. Gilreath Attorney-Larson and Taylor ABSTRACT: Synthetic plastic tape drawn from a controlled speed supply source is wound on a nonrotary support by means of mechanism comprising a winding guide for the tape which is driven round the axis of the support, while a relative axial traversing motion takes place between the guide and the support, so as to apply one turn of twist for each revolution of the guide. The tape is fed to the winding guide in a generally axial direction from a letotT guide and at a tension such that the twist is applied in a controlled manner represented by 10- calized folds to give a package from which the tape can be unwound overend in a twist-free condition.

PATENIEU FEB 2191: 5

sum 1 OF 4 PATENTED FEB 2 IBII sum 2 OF 4 PATENTED FEB 21971 SHEET 3 OF 4 PATENTED FEB 2 I97! SHEET 0F 4 WOUND PACKAGE This is a division of my previous application Ser. No. 665,6l5, filed Sept. 5, 1967. now U.S. Pat. No. 3,449,90l.

Synthetic plastics such as polypropylene and polyethylene may be produced in strip form by extruding the material as a sheet, slitting the sheet into narrow strips and then stretching the strips so as to align the molecules along the length of the strips. The stretching greatly enhances the strength of the material in a longitudinal direction to give a strip material referred to as a tape suitable for weaving on a loom. During the weaving process, however. the weft has a certain amount of twist inserted into it at irregular intervals and this has a deleterious effect on the cover of the cloth thus woven. In a normal construction of loom the weft is drawn from a cop or pirn, the diameter of which is limited to about l% inches. There is no particular problem in winding such a cop or pim without twist but the overend withdrawal inserts twist at an average rate of approximately one turn for every 3 inches of strip. With looms using a stationary weft supply the problem is not as marked but nevertheless still exists. With this type of loom the weft supply package is normally a 9 inches by 9 inches cone but again there needs to be overend withdrawal due to the high speed intermittent weft requirement and by the time the end of the cone is reached twist is being inserted at the rate of approximately one turn in every 6 inches.

A similar problem of twist insertion relates to the warp supply, namely, in the beaming of the tape intended for use as the warp. For this purpose a very large number of separate tapes needs to be drawn from packages mounted in a creel. The problem can be solved by using a spool with a sideways letoff but this eliminates the possibility of tag ending the packages which is highly desirable and which is only possible with overend withdrawal.

This general problem applies to a wide variety of plastic tapes of which polypropylene and polyethylene, which have already been mentioned, are the most important, but also including, for example, other polyolefins, acrylics, polyamides and so forth, that is to say, any synthetic tape which can be produced by an extrusion process.

The extrusion and slitting of a sheet of plastic gives rise to a large number of tapes which may either be wound directly on to the packages required for either warp or wefi supply in a continuous process directly from the extruder or alternatively may be collected on beams and then subsequently withdrawn and wound into packages in a separate operation. In either case a multispindle winding machine is necessary which receives the tapes at a controlled rate.

According to the present invention a synthetic plastic tape drawn from a controlled speed supply source is formed into a package by winding the tape on a nonrotary support by means of mechanism comprising a guide for the tape which is driven round the axis of the support, so that in this way one turn of twist is applied to the tape for each revolution of the guide. The tape is fed to the winding guide in a generally axial direction from the letoff guide at a tension such that the twist is applied in a controlled manner. The effect of the insertion of twist during winding is that if the tape is subsequently unwound from the package over the same end as that from which it was wound the outcome is to remove the twist applied during winding and to give a substantially untwisted strip. Thus a package wound in accordance with the present invention may be used either as a stationary weft supply for a loom or, for example, in a creel for the beaming of the warp supply and overcomes the difi'iculty referred to above. In other words it is possible to use overend withdrawal with the advantages of tag ending the packages but without the disadvantage of a twisted tape in the final product.

As mentioned above it is important to control tension in the tape during winding. If the tension is too high the tape will rope, i.e. longitudinal creasing of the tape takes place and a product is obtained which is very difficult to restore to its original state. If, on the other hand, the tension is too low the twisting action becomes erratic, and in addition a generally unacceptable package is formed.

Since the tape speed is controlled by the supply source. satisfactory control of tension can be achieved by a slipping drive to the winding guide. An equivalent result can be achieved in other ways, however, such as by use of a constant torque electric motor for the drive. A slipping drive is preferably achieved by transmitting the drive through a slipping clutch, but the slip may occur in the source of the drive itself, e.g. an air motor. Since the linear speed of the tape remains substantially constant during winding, the rotary speed of the winding guide must be varied with changes of diameter of the package. The drive to the guide must, of course, allow for this.

After leaving the letoff guide, the tape passes to the rotary mechanism and its first point of contact with the latter may either be the winding guide or some intermediate point. It is found that if the distance between the letoff guide and the contact point is kept relatively short this assists in maintaining regularity of the twist.

A number of other factors are also involved in controlling the insertion of twist and the relative importance of these varies with the design of the apparatus used and the operating conditions. The most important factor is, of course, the tension in the tape, the effect of which has already been discussed. Other important factors are the diameter of the letoff guide and the angle of the cone generated by the tape leaving the letoff guide. It is found advantageous for this angle to be of substantial size. By correctly shaping and positioning the letoff guide, or a part associated with it, relative to the cone angle of the tape it is found to be possible to control the nature of the folding action which results from the insertion of twist. Each winding revolution of the tape causes it to be pressed against the letoff guide and thus to be creased as a result of this pressing action in combination with the tension in the tape, thereby precreasing the tape at intervals corresponding to each revolution of winding. In this way it is possible to insert the twist in such a way that it is represented in the resultant package by localized folds spaced apart by relatively long lengths of flat or untwisted tape.

By the term "relatively long" is meant that at least 50 percent of the total length of the tape is untwisted, that is to say, is flat and has no twists or folds in it. In practice it may be possible for the folds to be considerably more localized than this so that a high proportion of the total length of the tape remains in an untwisted fomi. This is of importance for two reasons. In the first place once twist has been insertedin a tape and has been converted into a fold by the winding process there is a likelihood that the mark produced by the folding operation will remain even after the tape has been untwisted. By ensuring that a high proportion of the total length of the tape is unfolded the overall appearance of the tape is improved. A further advantage of localizing the folding action is that the lines of the folds are made at a rather greater angle to the axis of the tape rather than nearly parallel to the length of the tape as would be the case if the folds were more extensive. The more nearly a fold line is parallel to the length of the tape the greater the risk of fibrillation and this is an added reason for localization of the folding action.

Apparatus for winding a package in accordance with the method previously set out comprises a mounting for a stationary support for the package, a letoff guide mounted generally axially of the support, mechanism for driving a winding guide round the axis of the support, and for producing relative traversing movement between the guide and the support, and means for maintaining a suitable tension in the tape as the diameter of the package varies. The means for maintaining the tension may take any of the forms previously described.

The rotary mechanism for the winding guide. most conveniently takes the form of a flyer having the winding guide at or close to its lower edge and a contact point for the tape close to its top, which may be constituted by a bearing point on the shoulder of the flyer. As an alternative, however, the guide may be mounted on a ring which encircles the package to be wound and which is then driven to cause the guide to move around the axis of the stationary support and thus to carry out the required winding action. Whatever the form of mechanism, however, it is advantageous for the distance between the letoff guide and the first point of contact of the tape with the mechanism, whether constituted by the winding guide or a separate contact point, to be short.

A process and apparatus in accordance with the invention will now be described by way of example with reference to the accompanying drawings in which:

FIGS. 1A and 1B together show a complete production line including an extruder. stretching and stabilizing apparatus and finally winding apparatus;

FIG. 2 is a sectional view of an individual winding head;

FIG. 3 is a perspective view with part broken away of a flyer forming part of the winding head of FIG. 2;

FIG. 4 is a diagrammatic view of a length of tape unwound from a package produced on the winding head of FIG. 2; and

FIG. 5 shows parts of FIG. 4 to an enlarged scale illustrating the effect of the folding motion and the subsequent removal of the fold.

The majority of the components in the production line shown in FIGS. 1A and 1B are quite standard in themselves and require no detailed description. The figures are included, however, to illustrate the facility with which tapes produced by means of standard equipment may be wound in accordance with the present invention. Turning first to FIG. 1B the tapes shown as l emerge from an extruder and slitting unit 2 and then pass around a series of stretching rollers 3 which may, for example, stretch them by a factor of 7: 1. After stretching, the tapes pass through the stabilization ovens 4 and around stabilizing rollers 5. From there they pass to creel bars 6 fitted with a number of dividing pins 7 to space the individual tapes apart. Each tape then passes to its own individual winding head shown as 8 which will be described in more detail with reference to the subsequent figures. Components of the apparatus shown in FIG. 1B are all standard while the apparatus shown in FIG. 1A consists of a winding frame or frames indicated generally as 9 which comprises a multiplicity of winding heads 8 to wind the tapes coming from the extruder which in a typical example may be I04. The particular winding machine shown in FIG. IA is double sided for convenience.

FIG. 2 shows details of an individual winding head 8. Each head comprises a tubular flyer 12 shown in more detail in FIG. 3. Each flyer I2 is located on a spigot 13 on the upper end of a driving spindle 14. This spigot provides a driving connection to the flyer 12 but allows the flyer to be lifted off for the doffing of a finished package shown as 15.

A spindle 14 is mounted in a footstep bearing 18 and passes upwardly through bearings 19 in a reciprocating rail 20. The bearing 19 is mounted within a tube 21 which reciprocates with the rail 20 and which carries a second bearing 22 for the spindle 14. The spindle 14 is driven through a friction clutch arrangement indicated generally as 25. This comprises a belt pulley 26 which is driven by a belt (not shown) from a common source of drive for the machine as a whole. The pulley 26 is free to turn on the spindle 14 and engages a ring of friction pads 28 mounted on a flange 29 secured to the spindle 14 at 30. The friction pads 28 can be adjusted in a radial direction so as to vary the frictional drive between the pulley 26 and the flange 29 and hence the spindle 14. This provides the required control over the tension in the tape being wound.

A nonrotary support 34 for the package is removably fitted on a tube 35 having a radially extending arm 36 which is releasably attached at 37 to a vertically extending bar 38. This bar reciprocates with the rail to provide the relative traversing motion between the flyer I2 and the package 15.

In addition the bar 38 is adjustable in relation to the rail 20 so as to provide the necessary builder motion for the shaping of the ends of the package 15. For this purpose one face of the bar 38 is formed as a rack cooperating with a pinion 39 mounted on a shaft 40 which also reciprocates with the rail 20 and is given successive small angular movements as the rail reciprocates so as progressively to lower the bar 38 and hence the package IS in relation to the rail 20.

The tape shown as I passes from the respective creel bar 6 to a letoff point 45 on the axis of the flyer I2. This letoff point is constituted by a small freely rotatable roller from which the tape passes to a second control point defined by a bearing surface 46 on the shoulder of the flyer [2. From there the tape passes downwardly to a guide 47 constituted by a rotary runner and from there it is wound onto the stationary tube 34 so as to build up the package IS.

The tapes I will all reach the winding machine 9 from the extruder at a substantially constant speed and to allow for this the rotary speed of each package 15 needs to be reduced correspondingly as the package builds up. This result is achieved automatically by slipping of the clutch 25. The tension in each tape is controlled by adjustment of the clutch 25 as previously described.

The details of the flyer I2 and the path of the tape I will now be described in more detail with reference to FIG. 3. As can be seen from this FIG. the tubular wall of the flyer I2 is interrupted by access windows 50 and 51 which also lighten the construction since as previously mentioned the flyer as a whole needs to be removed for doffing.

The guide 47 runs on a stud 55 fixed to a plate 56 carried on the bottom skirt of the flyer, part of which is broken away to show the path of the tape onto the package 15. By mounting the guide 47 in this position the flyer is self-threading so that when the flyer is rotating it is merely necessary to hold the tape against the bottom skirt of the flyer whereupon it is automatically picked up by the guide 47 and wound onto the package.

In addition to the guide 47 the flyer comprises a light am 58 which is pivoted about a vertical axis defined by a tube 59 passing through the stud 55. Part of the arm 58 passes up the tube 59 and is held at its upper end by a stopper 60. The other end of the arm 58 is formed with a short extension 62 over which the tape passes immediately before being laid on the package I5. For this purpose the extension 62 is formed with tape-engaging surface, i.e. a small notch 63, which ensures accurate location of the tape 1 in an axial direction in relation to the package 15. The self-threading operation automatically lays the tape in the notch 63.

As shown in the drawings the arm 58 is freely pivoted and is merely held against the surface of the package 15 by the tension in the tape. In some circumstances it may be necessary to provide a biassing force so as to counteract the effect of centrifugal force on the arm 58 and thus to assist in holding the extension 62 against the surface of the package. This may be provided, for example, by a spring or by a counterweight mounted so that the centrifugal force on it tends to swing the arm 58 inwardly towards the package 15.

The tape passes over the roller 45 in a flat condition, being controlled laterally by the flanges of the roller, and twist is immediately inserted as shown in FIG. 3. In the angular position of FIGS. 2 and 3 the tape continues in the same general direction after leaving the roller 45, but by the time the flyer has turned through half a revolution a short length of tape (including the twist shown immediately following the roller 45 in FIG. 3) has been led around the underside of the roller 45 and pressed against it by the tension in the tape. Inspection of the apparatus during operation shows that the result of this is for the twisted tape to be creased as a result of pressure against the roller. This results from the diameter of the roller 45 which is large enough to provide sufficient bearing surface for creasing or folding the tape and the magnitude of the cone angle generated by the tape as it rotates (approximately 60 in the example shown) which causes sufficient length of tape to be led around the underside of the roller 45 as the flyer rotates. This effect is augmented by the short distance between the roller 45 and the bearing surface 46 which helps to ensure that twist is present in the length of tape which is pressed against the roller. Since the relative vertical positions of the roller 45 and the flyer 12 remain fixed during winding, the cone angle is constant and the conditions just described prevail throughout.

As an example of a construction which has been found to lead to good results on 1,000 denier polypropylene tape the roller 45 had a diameter of three-fourths inch, the vertical distance between the roller 45 and the bearing surface 46 was 3 3/16 inches the tension in the tape was 150 grams and the cone angle was approximately 60 as mentioned above.

FIG. 4 shows diagrammatically the effect of the localization of the folding action. seventy and 71 represent adjacent folds and these are separated by a much greater length 72 of unfolded tape. Even if the folding is not as highly localized as shown in FIG. 4 the provision of the control region provided by the points 45 and 46 nevertheless leads to considerable uniformity in the folding action.

This folding action is illustrated to a considerably larger scale in FIG. 5. in the top part of FIG. 5. 73 shows a pair of closely spaced folds representing one complete turn of twist and corresponding to either 70 or 71 in FIG. 4. It will be seen that the fold lines are at an appreciable angle to the axis of the tape so that the folding is localized and thus leads to the relatively great unfolded length 72 of FIG. 4. When the tape is subsequently unwound from the package by withdrawing it over the same end of the package as that from which it was wound the twist is progressively taken out to leave an untwisted tape as previously described. Although the twist may have been removed the fold lines are still visible and in the lower part of FIG. 5, 74 shows the untwisted tape exhibiting the lines resulting from the folds indicated at 73. Owing to the fact that those lines are localized they have no marked adverse effect on the appearance of the tape and moreover their angle to the axis of the tape avoids any serious danger of fibrillation which might otherwise occur with fold lines more nearly parallel to the axis of the tape as would be the case if the folding were not localized.

I claim:

I. A wound package comprising windings of synthetic plastic tape. said tape being a generally flat strip of material. said package having for each of said windings an average of one complete turn of twist in the form of localized folds. each said localized fold constituted by a bending of the generally flat tape about a crease line, at least one localized fold of each turn of twist being separated from at least one of its adjacent folds on the tape by a length of untwisted tape.

2. A wound package according to claim 1, wherein the said length of untwisted tape is a relatively long length, relative to the length along the tape of a fold.

3. A wound package according to claim 1, wherein the localized folds occur in pairs, the folds of each pair being relatively close together, each pair of folds being separated from its adjacent pair of folds by said length of untwisted tape, which length is relatively long in comparison to the length along the tape of a pair of folds.

4. A wound package according to claim I, each individual localized fold being separated from its adjacent fold by a length of untwisted tape.

5. A wound package according to claim 4, wherein the said length of untwisted tape is a relatively long length, relative to the length along the tape of a fold.

6. A wound package according to claim 1, said package being wound onto a central core. 

1. A wound package comprising windings of synthetic plastic tape, said tape being a generally flat strip of material, said package having for each of said windings an average of one complete turn of twist in the form of localized folds, each said localized fold constituted by a bending of the generally flat tape about a crease line, at least one localized fold of each turn of twist being separated from at least one of its adjacent folds on the tape by a length of untwisted tape.
 2. A wound package according to claim 1, wherein the said length of untwisted tape is a relatively long length, relative to the length along the tape of a fold.
 3. A wound package according to claim 1, wherein the localized folds occur in pairs, the folds of each pair being relatively close together, each pair of folds being separated from its adjacent pair of folds by said length of untwisted tape, which length is relatively long in comparison to the length along the tape of a pair of folds.
 4. A wound package according to claim 1, each individual localized fold being separated from its adjacent fold by a length of untwisted tape.
 5. A wound package according to claim 4, wherein the said length of untwisted tape is a relatively long length, relative to the length along the tape of a fold.
 6. A wound package according to claim 1, said package being wound onto a central core. 